Schröter is a lunar crater near the mid-part of the Moon, on the eastern Mare Insularum, and named after German astronomer Johann Hieronymus Schröter. The rim of Schröter is heavily worn and eroded, with a wide gap in the southern wall and a deep indentation to the southeast. There is no central peak at the crater's mid-point. To the north of Schröter, beginning with the satellite crater Schröter W, is a region of irregular terrain. This area includes an array of linear dark surface markings that appear to criss-cross. In the 19th century, Franz von Gruithuisen is noted for claiming that this area contained a lunar city, based on his observations using a small refracting telescope. This inference was greeted with considerable skepticism by astronomers at the time, and, indeed, subsequent observations with more powerful instruments demonstrated that this was merely a natural feature. Source